We assess the relationship between general literacy skills and health status by analysing data from the Programme for the International Assessment of Adult Competencies (PIAAC), an international survey of about 250 000 adults aged 16-65 years conducted by the Organisation for Economic Co-operation and Development (OECD) from 2011-15 in 33 countries/national sub-regions. Across countries, there seems to be a strong and consistent association between general literacy proficiency and self-rated poor health, independent of prior socio-economic status and income. General literacy proficiency also appears to be a mediator of the association between self-education and self-rated poor health. While the literacy-health association is robust over time, it varies in magnitude across countries. It is strongest for those with a tertiary or higher degree and does not appear to exist among young adults (ages 25 to 34 years). Future studies are required to understand the contextual factors that modify the general literacy proficiency-health association.